Pavement markers (e.g., paints, tapes, and individually mounted articles) guide and direct motorists and pedestrians traveling along roadways and paths. Pavement markers are used on, for example, roads, highways, parking lots, and recreational trails, to form stripes, bars and markings for the delineation of lanes, crosswalks, parking spaces, symbols, legends, and the like. The formed or applied traffic lines created by these pavement markers form a part of the road surface and are thus subjected to the wear and destructive action of traffic.
Many types of pavement markers are applied directly to a roadway or pavement. Because the pavement markers must stick or adhere to the roadway or pavement surface, they require a dry surface to achieve acceptable adhesion. The requirement of a dry surface significantly limits the available time when pavement markers can be applied because it effectively eliminates pavement marker application during times of wet precipitation (e.g., rain or snow) or when the roadway is wet.
Currently, adhesion to these substrates is typically improved somewhat by two means: use of a flame torch and a primer composition. Using a flame torch to dry the roadway is a labor intensive and thus expensive process.
Existing primer compositions typically include a polymeric primer in organic solvent which is brushed or sprayed onto the surface before the pavement marker is applied, as described in U.S. Pat. Nos. 3,902,939, 3,518,107 and PCT Patent Publication No. WO 94/00519 (incorporated by reference herein in their entirety). Examples of primer compositions include organosols, such as disclosed in U.S. Pat. No. 4,906,523 (Bilkadi et al.), and the use of solutions of high molecular weight rubbers in organic solvents
Problems still exist, however, in that traffic markings applied to damp surfaces using these primers continue to separate from the roadway after short exposures to traffic and continued weathering.